Plaster material for making fresco-like finish

ABSTRACT

The fresco coating composition which, when admixed with a cement-based plaster, produces a material for troweling, to obtain fresco finish. The composition is made by combining: a) 10 to 24% by weight of at least one binder selected from the group consisting essentially of an acrylic polymer binder or an acrylic polymer binder and an acrylic polymer cross-linking binder; b) 20 to 50% by weight of water; c) 2 to 8% by weight of a filler selected from the group consisting essentially of cellulose, paper pulp, or mixtures thereof; d) 20 to 40% by weight of at least one water-insoluble particulate extender including silica sand; e) 0.5 to 2% by weight of a thickening agent; f) optionally at least one of a solvent, a coalescence promoter, a foam inhibitor, a biocide and mixtures thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.08/850,649 filed May 2, 1997, now U.S. Pat. No. 5,741,844, which is acontinuation of U.S. application Ser. No. 08/153,430 filed Nov. 16,1993, now abandoned.

BACKGROUND OF THE INVENTION

1.Field of the Invention

The present invention relates to a plaster wall surface having afresco-like appearance. More specifically, the present invention isdirected to a coating composition, plaster material, a method forapplying the plaster material to a wall to obtain a fresco-like finishand the fresco-like plaster wall surface created thereby.

2. Description of the Related Art Including Information Disclosed Under37 CFR §§ 1.97-1.99

Heretofore various techniques have been proposed for creating a wallfinish that has random swirls or designs, e.g. marble-like, with varyingcolor density, i.e., with lighter portions and darker portions of thesame basic color.

A new technique for providing such a finish has been referred to as afaux finish and several methods for creating such finishes are disclosedin the in the

    ______________________________________                                        U.S. Pat. No.       Patentee                                                  ______________________________________                                        3,915,917           Weiant, et al.                                              4,059,551 Weiant, et al.                                                      4,088,804 Cornwell et al.                                                     4,142,911 Ellis et al.                                                        4,159,301 Buser et al.                                                        4,267,091 Geelhaar, et al.                                                    4,330,458 Spinelli, et al.                                                    4,339,365 Becher, et al.                                                      4,354,912 Jasperson                                                           4,708,745 Schonhausen                                                         4,710,540 McAlpin                                                             4,946,715 Ronald Avera                                                        5,084,303 Ronald Avera                                                        5,122,395 Raymond Sandor                                                      5,164,433 Ricci et al.                                                        5,308,890 Snyder                                                            ______________________________________                                    

Before the advent of the faux finishes, fresco painting has beenutilized for centuries to obtain a fresco finish; the frescomural-painting technique involved painting permanent lime-proof pigmentsdispersed in water on freshly laid lime plaster.

In fresco paintings, mineral colors are applied in a thin(0.001-0.003-in.) layer to wet plaster surfaces and, as a result ofenvironmental exposure to carbon dioxide, the calcium lime is convertedto calcium carbonate which retains the pigment and on drying imparts tothe surface a marble-like appearance. Fresco coatings which are appliedby trowel or similar device have a thickness of 0.005-0.25 in. and thesecoatings exhibit, on drying, a marbled texture whose appearance isenhanced by the presence of a colorant (dye) and paper pulp additive inthe formulation. The dye is absorbed preferentially on the hydrophilicfibers of the pulp thereby highlighting the visual attributes of thecoating.

In a fresco, the pigments are absorbed into the wet wall by capillaryaction and become an integral part of the wall's surface. Indoors, on aproperly prepared support, fresco is one of the most permanent paintingtechniques. Its colors are stable, not because they are protected by acalcareous film or "limeskin"--as formerly believed--, but because theyare made with chemically inert pigments. Fresco is not adaptable toexterior murals; its chief enemies are polluted air and abrasion bywindbome particles.

Fresco meets all the requirements for an ideal mural painting: it has aperfectly mat surface; its color effect is brilliant; it lends itselfespecially to monumental styles; and it ages nobly.

As will be described in greater detail hereinafter, the presentinvention provides a coating composition including a number of elements,a plaster material including the coating composition, a method formixing and applying the plaster material and coating compositioncombination to a wall, a surface, or a ceiling to obtain a fresco-likefinish, and a fresco-like plaster wall, surface, or ceiling formedthereby.

SUMMARY OF THE INVENTION

According to the present invention there is provided a fresco coatingcomposition which, when admixed with a cement-based plaster, produces amaterial for troweling to obtain a fresco finish, said composition beingmade by combining:

a) 10 to 24% by weight of at least one binder selected from the groupconsisting essentially of an acrylic polymer binder, an acrylic polymerbinder and an acrylic polymer cross-linking binder;

b) 20 to 50% by weight of water;

c) 2 to 8% by weight of a filler selected from the group consistingessentially of cellulose, paper pulp, or mixtures thereof;

d) 20 to 40% by weight of at least one water-insoluble particulateextender including silica sand;

e) 0.5 to 2% by weight of a thickening agent;

f) optionally at least one of a solvent, a coalescence promoter, a foaminhibitor, a biocide and mixtures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The file of this patent contains at least one photograph executed incolor. Copies of this patent with the color photograph will be providedby the Patent and Trademark Office upon request and payment of thenecessary fee.

FIG. 1 is a photograph of a fresco-like wall surface of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Referring now to FIG. 1, there is depicted in the photograph afresco-like finish obtained using a coating composition comprising aplurality of ingredients to give a slightly rough but yet smooth finishwhen mixed with plaster and a colorant using the method of the presentinvention described in greater detail hereinafter.

    ______________________________________                                        INGREDIENT         PERCENTAGE BY WEIGHT                                       ______________________________________                                        The coating composition is a mixture of a plurality of                          ingredients which are listed below                                            Latex polymers binder,                                                                             10-30%                                                   acrylic polymer binder, or two                                                acrylic polymer cross-linking binders                                         Extenders 10-30%                                                              Filler  5-20%                                                                 Water 20-45%                                                                  Solvents  6-15%                                                               Latex coalescence promoters 1-2%                                              Thickening agents  5-15%                                                    The coating composition may also optionally employ the                          ingredients which are listed below                                            Surfactants          0.03-0.2%                                                Foam inhibitors 0.1-0.3%                                                      pH adjuster 0.1-0.2%                                                          Biocides 1-3%                                                                 Mildewcide 0.1-0.5%                                                           Colorant 2-8%                                                               ______________________________________                                    

When prepared, the above fresco coating composition of the presentinvention has the consistency of heavy molasses, can be spread by trowelon a wall, a surface, or a ceiling to be coated (e.g. plaster, drywall,metal) to leave on it a thin layer of coating. The uniqueness of thiscoating lies in the fact that, in addition to its protection of thesubstrate against environmental influences, it imparts to the wall,surface, or ceiling the appearance of an ornamental fresco. However,unlike the frescoes of the famous Italian painters of the Renaissanceperiod whose paintings had to be applied to wet plaster, the frescocoating of the present invention can be deposited on a dry substratewhile still eliciting the desired optical effect.

A high molecular-weight organic binder which holds solid particulates inits matrix and prevents mechanical breakdown of the coating comprises anessential ingredient in the fresco formulation. The binder used for thispurpose also facilitates the deposition of a smooth and adherent coatinglayer on a wall, ceiling or other surfaces, and it promotes developmentof a fresco texture. According to the present invention polymers thatcan be used in aqueous emulsions to accomplish this objective areacrylics, poly(vinyl acetate), poly(vinyl chloride), copolymers ofstyrene and butadiene, and polyurethanes.

The emulsion binding polymers of choice are the acrylic latex polymersincluding methyl methacrylate, butyl- or isobutyl-methacrylate theirblends, and homologs with longer chain substituents. The use of anacrylic emulsion polymer is important in fresco coating of the presentinvention due to its pigment-binding capability in formulation of amarble-like texture and cast films. For example, the acrylic binder ofthe fresco coating composition of the present invention may includeRHOPLEX MULTILOBE-200, an all-acrylic binder supplied by Rohm & HaasCo., Philadelphia, Pa., which imparts chalk resistance, adhesion andpigment retention to coatings in paint formulations. Other Rohm & Haasproducts of RHOPLEX AC-261, an acrylic emulsion polymer with abrasionresistance, RHOPLEX HG-74M, a styrene containing acrylic claimed toprovide hardness in enamel-like coatings, and RHOPLEX WL-96 anacrylonitrile-containing latex with outstanding adhesion to metal andplastic surfaces, flexibility and mar resistance are all suitableacrylic emulsion polymers for the present invention.

RHOPLEX MULTILOBE 200 is an acrylic emulsion polymer typicallycomprising 53 to 54% acrylic polymer, less than 1% of individualresidual monomers, 0.2% maximum of aqua ammonia, and 46 to 47% water. Ithas a viscosity of 300-1500 cpd; a molecular weight greater than1,000,000, a glass transition temperature of 9.0° C., a gel content(gm./qt.) At 100 mesh of 0.05 gm./qt. Maximum and at a 325 mesh 0.10gm./qt. Maximum, and a dry bulking value (lb./gal.) Of 0.107.

RHOPLEX AC-261 is an acrylic emulsion polymer for latex floor paintstypically comprising 49 to 51% of acrylic copolymer, less than 0.1%individual residual monomers, 0.2% maximum of ammonia, and 49 to 51%water. The solid content of acrylic copolymer of RHOPLEX AC-261 is 50%+/-0.5%. RHOPLEX AC-261 has a pH of 9.0 to 10.0, a viscosity of 100 TO500 cps (Brookfield Model LVT, #2 spindle at 60 r.p.m.), a gel contentat 100 mesh of 0.05 gm./qt. And at a 325 mesh, 0.10 gm./qt., a density,deaerated, of 8.82 lb./gal. And a dry bulking value of 0.106 gal./lb.

RHOPLEX HG-74M is an acrylic copolymer emulsion typically comprising 41yo 43% acrylic polymer, less than 0.1% individual residual monomomers,0.1% maximum ammonia and 57 to 59% water. RHOPLEX HG-74M has amilky-white liquid appearance, a solid content of 42%, a pH of 7.5 to8.5, a Brookfield Viscosity (#3 spindle, at 60 r.p.m.) Of 800 cps, adensity of 8.6 lb./gal., a bulking value of dry solids of 0.112gal./lb., a specific gravity of 1.03 g/l and a minium film formationtemperature of 30° C.

The coating composition prepared with an emulsion polymer binder oracrylic polymer binder imparts a sufficient fresco-like finish to thecoating composition when mixed with a cement based plaster, however useof two acrylic polymer cross-linking binders in the coating compositionof the present invention yields a preferred superior fresco-like finishwhen mixed with cement based plaster. Apparently, the surfaceirregularities that contribute to the fresco pattern result fromstress-induced dimensional changes within the plane of the coating layerlikely attributed to the use of two reactive (cross-linking) acryliccompounds in the coating mixture. These dimensional changes can beattributed to the contraction of the coating during polymerization andcross-linking of the binder resin.

Blending of the two acrylic polymer binders becomes important where acertain degree of rigidity (hardness) or flexibility of the frescocoatings has to be maintained. In these instances, the combination ofacrylic latexes with short- and long-chain substituents will result incoatings with a lesser or greater flexibility, respectively. Thecopolymers of substituted methacrylates show decreasing hardness andincreasing flexibility for polymers with chain substituents ofincreasing length and frequency of occurrence. Thus, poly(methylmethacrylate) which is the primary compound in plastic window pane(Lucite, Plexiglass) is significantly harder than copolymers of methylmethacrylate (M.A.) with butyl methacrylate (Bema) or isopropylmethacrylate (IPA).

The two cross-linking acrylic polymer binders may be selected from thegroup comprising: poly(methyl methacrylate), methyl methacrylate (M.A.),butyl methacrylate (BuMa), isopropyl methacrylate (IPMA), and RHOPLEXMULTILOBE-200, RHOPLEX AC-261 RHOPLEX 186-74 or RHOPLEX WL-96. Thepreferred acrylic latex blend represents a mixture of 50%solids-containing poly(methyl)- and poly(butyl)- methacrylate in 2:1-1:5weight proportions. The preferred amount of combined latexes ranges from10-30 wt.-% per total weight of formulation ingredients, depending onthe amount of filler and extender used.

Polyethylene glycol diacrylate and trimethyl triacrylate can be used ascross-linking agents to improve the structural properties of the acrylicemulsion polymers.

A latex coalescence-producing agent, such as TEXANOL available from theEastman Chemical Products, Co., can be used with the binding polymer(s)of the present invention, such as with RHOPLEX AC-261, RHOPLEX HG-74M,and RHOPLEX WL-96 in the weight percentages of 5, 15 and 20%respectively to obtain cohesiveness (compaction, hardness). Aformulation additive capable of enhancing coalescence of latex particlesimproves the physical and mechanical properties of film cast from thelatex. Furthermore, it is conceivable that better coalescence of theemulsion could result in visual differences of "islets" at the filmsurface, thereby producing effects of marbling in the coating,particularly in those instances where the acrylic polymer would show agreater tendency to dye absorption (staining) than the inorganicconstituents in the coating.

The extender may include clay, titanium dioxide, silica, calcined clay,calcium carbonate, calcium sulfate and other water insolubleparticulates and mixtures thereof. These extenders may comprise 10-30%of the total weight of ingredients. A preferred extender is powderedclay of the type which can be purchased from Whittaker, Clark & Danielsunder the brand name of SNOW-BRITE CLAY.

The coating composition of the present invention includes thickeningagents in the amount of 5-15% by weight. A preferred thickener is thetype which can be purchased from Aqualon Co. under the brand nameNATROSOL 250MHR.

The filler of the coating composition of the present invention ispreferably fine silica sand for a primary base coating and is a pulpfiller for second and/or finish coatings. The pulp filler is preferablypaper pulp of 1-5 mm fiber length, and most preferably 1.5 to 3 mm fiberlength as obtained from softwood, and is used in wet form in amounts of5-20% by total weight of formulation ingredients. The use paper pulp asan additive in the fresco coating suggests the possibility of watermigration from the coating to the underlying substrate through thewickening action of pulp fibers, thereby contributing to shrinkage ofthe surface layer and the fresco-causing effect of the surface.Alternatively, the pulp filler may comprise wood pulp. The presence ofwood pulp in an amount of 5-20% enhances "marbling" of the coating incomparison with coating without wood pulp, particularly afterintroduction of a colorant into the system. Apparently, the greateraffinity of the wood pulp toward the dye in comparison with inorganic(silica, cement, clay) sorbents, and the non-uniform distribution of thepulp in the system are responsible for the observed effects.

The coating composition of the present invention also includes solventssuch as propylene glycol and methyl carbitol to reduce the drying timefor the coating.

The formulation of the present invention is diluted with water (20-45wt.-%) to obtain a slurry-like consistency and permit its reaction withPortland cement.

The coating composition of the present invention may also optionallyinclude a number of additional ingredients. Particularly, surfactantsmay be added in the amount of 0.03 to 0.2% by weight of the formulation.A preferred surfactant is available from Union Carbide Co. under thebrand name SILWET L-77. A foam inhibitor may also be included in theamount of 0.1-0.3% by weight of formulation. A preferred foam inhibitoris available from Dow Chemical Co. under the brand name ofANTIFOAM-1410. Additionally, a pH adjuster, biocide, and mildewcide maybe included in the composition of the present invention.

After the coating composition of the present invention has beenprepared, then pigment (dye) or other tint or colorant preferably in theamount of one ounce colorant per pound of coating composition may beadded to the coating composition to impart to the total formulation thedesired color.

Prior to the introduction of cement to the coating composition, theformulation ingredients including the colorant are preferably mixed for15-20 min. using high rate, high-shear mixing equipment. The cementplaster then is admixed to the formulation in weight proportions of 1:1to 2:5 for cement and coating composition respectively. The cement ispreferably Portland Cement but use of Keene's Cement, White PortlandCement, or White Medusa Cement may be appropriate in some applications.Portland Cement is preferable as it is readily available, does not setfast, and is good to use in aqueous environments.

For example, a coating composition according to the present inventionmay be mixed with a colorant and a cement in the following ratios: 10ounces of colorant, such as sold by Benjamin Moore Paint Company, and 7pounds of plaster to 10 pounds of coating composition. The aboveingredients for the plaster composition is thoroughly mixed. Then it isallowed to sit for approximately five minutes to allow it to "take up"or "tighten".

Then it is remixed thoroughly for one minute and is ready to apply.

A first base or "primer" coat of the batch of the plaster composition istroweled evenly and smooth on a flat surface and allowed to set and dryfor 24 hours. This primer coat utilizes fine silica sand as a fillerinstead of paper pulp or wood pulp (see Table 4 hereinafter). Then asecond or "finish" coat is applied with circular and irregular trowelingto obtain a fresco-like, or marble like, finish. The finish coat usespaper pulp or wood pulp as a pulp filler.

The resulting plaster wall finish is shown in FIG. 1 and is not onlyvery attractive but also has a number of advantages.

First of all, since the color extends completely through both thefirst/primer and second/finish coatings, this plaster wall surface isideally suited for indoor use.

Secondly, since the color extends completely through the material,whenever there is an abrasion or mark on the wall surface, it can beeasily repaired by sanding the wall in the area of the mark or abrasionwith a very fine sandpaper, e.g. 600 to 2,000 grade sandpaper.

Thirdly, by having a latex base the plaster wall, ceiling, or surfacecan be washed with soap and water.

EXAMPLES

The preferred coating composition of the present invention includes tworeactive cross-linking acrylic compounds in the coating mixture. Table 1and Table 2 below set forth examples of the preferred "finish" frescocoating composition having two acrylic polymer cross-linking binderswith ingredients and amounts required to prepare 10 and 50-lb. batches:

                                      TABLE 1                                     __________________________________________________________________________    FRESCO COATING COMPOSITION                                                      (Formulated for addition of cement batch)                                                                           Amount                                                                             Amount                                AMOUNT Wt-% for 10-lb for 50-lb                                            INGREDIENT FUNCTION MANUFACTURE gram partial (lbs) (lb)                     __________________________________________________________________________    NATROSOL 250 MHR                                                                          Thickener                                                                            Aqualon Co. 12.00                                                                              5.58                                                                              0.56 2.79                               Propylene glycol Solvent Aldrich Chem. Co. 3.06 1.42 0.14 0.71                Methyl carbitol Solvent Aldrich Chem. Co. 25.60 11.99 1.20 6.00                                                           SILWET L-77 Surfactant                                                       Union Carbide Co. 0.15 0.07                                                   0.01 0.03                          SNO-BRITE CLAY Extender Whittaker, Clark & Daniels 24.80 11.53 1.15                                                      5.76                               Methyl carbitol Solvent Aldrich Chem. Co.                                     Water   83.15 38.65 3.86 19.32                                                Paper pulp Filler Dance Paper Co. 11.3 5.25 0.53 2.63                         RHOPLEX AC-261 Acrylic binder Rohm & Haas 15.00 6.97 0.70 3.49                RHOPLEX Multilobe-200 Acrylic binder Rohm & Haas 36.5 16.96 1.70 8.48                                                     TEXANOL Coalescent Eastman                                                   Chemical Co. 3.00 1.39 0.14                                                   0.70                               ANTIFOAM-1410 Defoamer Dow Chemical Co. 0.40 0.19 0.02 0.09                 __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________    FRESCO COATING COMPOSITION                                                      (Formulated for addition of cement batch)                                                                           Amount                                                                             Amount                                AMOUNT Wt-% for 10-lb for 50-lb                                            INGREDIENT FUNCTION MANUFACTURE gram partial (lbs) (lb)                     __________________________________________________________________________    NATROSOL 250 MHR                                                                          Thickener                                                                            Aqualon Co. 18.00                                                                              6.40                                                                              0.64 3.20                               Propylene glycol Solvent Aldrich Chem. Co. 4.59 1.63 0.16 0.82                Methyl carbitol Solvent Aldrich Chem. Co. 38.70 13.76 1.38 6.88                                                           SILWET L-77 Surfactant                                                       Union Carbide Co. 0.23 0.08                                                   0.01 0.04                          SNO-BRITE CLAY Extender Whittaker, Clark & Daniels 37.20 13.23 1.32                                                      6.62                               Water   83.15 29.57 2.96 14.79                                                Paper pulp Filler Dance Paper Co. 16.95 6.03 0.60 3.01                        CR-750 Styrene-acrylic Binder B.F. Goodrich 10.00 3.56 0.36 1.78                                                          RHOPLEX AC-261 Acrylic                                                       binder Rohm & Haas 12.5 4.45                                                  .44 2.22                           RHOPLEX Multilobe-200 Acrylic binder Rohm & Haas 54.75 19.47 1.95 9.74                                                    TEXANOL Coalescent Eastman                                                   Chemical Co. 4.50 1.60 0.16                                                   0.80                               ANTIFOAM-1410 Defoamer Dow Chemical Co. 0.60 0.21 0.02 0.11                 __________________________________________________________________________

Since the presence of organic compounds in fresco coatings increasestheir susceptibility to deterioration as a result of micro organicaction, it is desirable to include a biocide in coating formulations topreserve the coating during storage and prevent its degradation throughbacterial and fungal action.

Among compounds that are capable of accomplishing this objective are thewater-based nonmetallic preservatives 5-hydroxymethoxymetyl-1-aza-3, 7dioxybicyclo(3.3.0) octane, and tetrachloroisophthaTonirile. Thesepreservatives are commercially available from Huls America, Inc. underthe trade names of NUOSEPT-95 and NUOCIDE 404D, respectively. The firstcompound is a bactericide that is used in amounts of 1.0-2.8% by weightof coating, while the second compound is a fungicide/mildewcide used at0.1-0.5 wt-%.

An example of the finish fresco coating formulation containing theseshelf-life extending preservatives are listed in Table 3 below:

                                      TABLE 3                                     __________________________________________________________________________    FRESCO COATING COMPOSITION                                                      (Formulated with preservatives)                                                                                     Amount                                                                             Amount                                AMOUNT Wt-% for 10-lb for 50-lb                                            INGREDIENT FUNCTION MANUFACTURE gram partial (lbs) (lb)                     __________________________________________________________________________    NATROSOL 250 MHR                                                                          Thickener                                                                            Aqualon Co. 12.00                                                                              5.73                                                                              0.57 2.86                               Propylene glycol Solvent Aldrich Chem. Co. 3.06 1.46 0.15 0.73                Methyl carbitol Solvent Aldrich Chem. Co. 25.80 12.31 1.23 6.15                                                           SILWET L-77 Surfactant                                                       Union Carbide Co. 0.15 0.07                                                   0.01 0.04                          SNO-BRITE CLAY Extender Whittaker, Clark & Daniels 24.80 11.88 1.18                                                      5.92                               Water   76.45 38.48 3.65 18.24                                                Paper pulp Filler Dance Paper Co. 11.3 5.89 0.54 2.20                         RHOPLEX AC-261 Acrylic binder Rohm & Haas 12.99 6.25 0.62 3.10                RHOPLEX Multilobe-200 Acrylic binder Rohm & Haas 36.5 17.41 1.74 8.71                                                     TEXANOL Coalescent Eastman                                                   Chemical Co. 3.00 1.43 0.14                                                   0.72                               ANTIFOAM-1410 Defoamer Dow Chemical Co. 0.40 0.19 0.02 0.10                   NUOCIDE-4040 Biocide Huls America, Inc. 2.89 1.38 0.66 0.63                   NUOSEPT-95 Mildewcide Huls America, Inc. 0.25 0.11 0.06 0.06                __________________________________________________________________________

Any of the Fresco coating compositions set forth in Tables 1, 2, and 3above, can also be used in conjunction with a primer base coatingcomposition. As previously noted the primer base coat utilizes finesilica sand as a filler instead of a pulp filler such as paper pulp orwood pulp. An example of a primer base coat according to the presentinvention for Fresco coating compositions of the present invention isset forth below as Table 4:

                                      TABLE 4                                     __________________________________________________________________________    PRIMER BASE COAT FOR FRESCO COATING COMPOSITION                                                              WT-% AMOUNT FOR                                  INGREDIENTS FUNCTION MANUFACTURE PARTIAL 50 lb. BATCH                       __________________________________________________________________________    NATROSOL 250 MHR                                                                          Thickener                                                                            Aqualon Co. 4.96 2.48                                        Propylene Glycol Solvent Aldrich Chem. Co. 1.26 0.63                          Methyl Carbitol Solvent Aldrich Chem. Co. 10.70 5.35                          SILWET L-77 Surfactant Union Carbide Co. 0.06 0.03                            SNO-BRITE CLAY- Extender Whittaker, Clark & Daniels 10.30 5.15                BRITE CLAY-Brite Clay                                                         Water   31.72 15.86                                                           Fine Silica Sand Filler Wedron Silica Co. 17.76 8.88                          RHOPLEX AC-261 Acrylic Binder Rohm & Haas 5.38 2.69                           RHOPLEX Multilobe-200 Acrylic Binder Rohm & Haas 15.14 7.57                   TEXANOL Coalescent Eastman Chem. Co. 1.24 0.62                                ANTIFOAM-1410 Defoamer Dow Chemical Co. 0.18 0.09                             NUOCIDE-404D Biocide Huls America, Inc. 1.20 0.60                             NUOSEPT-95 Mildewcide Huls America, Inc. 00.10 0.05                               50.00                                                                   __________________________________________________________________________

Each of the finish Fresco coating compositions of Tables 1, 2, and 3above, and the primer base coating composition of Table 4 above areformulated for the addition of a cement batch. When the coatingcomposition has been made, the composition is then thoroughly mixed forapproximately 20 minutes. Once so mixed, the composition is ready forthe addition of a cement batch. The cement, preferably Portland cement,is admixed to the coating composition of Tables 1, 2, or 3 above in aweight proportion of 1:1 to 2:5 for cement to coating compositionrespectively, and preferably is mixed in the amount of 7 pounds ofcement to 10 pounds of coating composition.

In contradistinction to the preferred coating compositions of Tables 1through 4 above having two acrylic polymer cross-linking binders, thefollowing finish coating compositions described in Tables 5 through 9employ a single binder. Single binder compositions did not have thehardness and consistency of the two acrylic polymer cross-linking binderformulations. Examples of single binder formulations are set forth belowin Tables 5 through 9:

                                      TABLE 5                                     __________________________________________________________________________    FRESCO COATING COMPOSITION                                                    __________________________________________________________________________    INGREDIENT    FUNCTION                                                                             MANUFACTURE                                                                              TOTAL   Partial A                             __________________________________________________________________________      NATROSOL 250 MHR Thickener Aqualon Co. 11.8  21.57                            Ethylene glycol Solvent Fisher Chem. Co. 2.4  4.39                            Propylene glycol Solvent Fisher Chem. Co. 3.4  6.21                           TEXANOL-1124 Dispersant Rohm & Haas 0.44  0.80                                Triton-CF10 Surfactant  0.1  0.18                                             Colloid-643 Defoamer Colloids, Inc. 0.19  0.35                                Ti-pure R902 TiO2 Du Pont 14.4  26.32                                         Minex 4 Silicate, ext. Indusmin, Inc. 4.8  8.77                               Icecap K Extender Unimin Spec. Chemicals 1.4  2.56                            RHOPLEX MULTILOBE-200 Acrylic Binder Rohm & Haas 11.48  20.98                 Celite 281 Diatom. silica Johns Manville Co. 4.3 54.71 7.86                 __________________________________________________________________________           Partial B                                                              __________________________________________________________________________      RHOPLEX MULTILOBE-200 Acrylic Binder Rohm & Haas 32.37  1.32                  Texanol Coalescent Eastman Chemical Co. 1.1  2.43                             Colloid Defoamer Colloids, Inc. 0.19  0.42                                    Natrosol 250 MHR Thickener Aqualon Co. 4.71  10.40                            Ammonia (28%) pH adjuster Fisher Chemical Co. 0.06  0.13                      Water   6.93 45.29 15.00                                                          100                                                                     __________________________________________________________________________

                                      TABLE 6                                     __________________________________________________________________________    FRESCO COATING COMPOSITION                                                    __________________________________________________________________________                                   AMOUNT                                                                             Wt-%                                        INGREDIENT FUNCTION MANUFACTURE gram partial Total                          __________________________________________________________________________      Natrosol 250 MHR Thickener Aqualon Co. 12.00 14.34 10.91                      Glycerine Solvent Fisher Chem. Co. 6.00 7.17 5.45                             KELCO Dispersant KELCO CO. 0.40 0.48 0.36                                     Triton-CF10 Surfactant  0.10 0.12 0.09                                        SIL Defoamer Union Carbide Co. 0.20 0.24 0.18                                 Silica Extender  4.30 5.14 3.91                                               Snowbrite clay Extender H.B. Fuller Co. 20.20 24.13 18.36                     RHOPLEX MULTILOBE-200 Acrylic Binder Rohm & Haas 16.70 19.95 15.18                                                       Water   13.70 16.37 12.45                                                     Wet Pulp   10.10 12.07 9.18      Grind ingredients 20 min. then add:                                                                          83.70                                                                              100.00                                                                            76.09                                 __________________________________________________________________________                                   wt-%     mixture/cement                                                       Partial                                                                            Total                                                                             wt-%                                  __________________________________________________________________________                                                60.69                             Cement               Portland Cement Co.                                                                     8.80 33.46                                                                             8.00                                    Mixture  14.50 5.13 13.18                                                     Water  3.00 11.41 2.73                                                      __________________________________________________________________________

                                      TABLE 7                                     __________________________________________________________________________    FRESCO COATING COMPOSITION                                                    __________________________________________________________________________                                   AMOUNT                                                                             Wt-%                                        INGREDIENT FUNCTION MANUFACTURE gram partial Total                          __________________________________________________________________________    Natrosol 250 MHR                                                                            Thickener                                                                            Aqualon Co.                                                                             12.00                                                                              11.76                                                                             7.68                                    Glycerine Solvent Fisher Chem. Co. 6.00 5.88 3.84                             KELRAN, guar gum Dispersant KELCO CO. 0.40 0.39 0.26                          SILWET L-77 Surfactant Union Carbide Co. 0.10 0.12 0.06                       ANTIFOAM 1410 Defoamer Dow Corning Corp. 0.20 0.20 0.13                       Silica Extender  4.30 4.22 2.75                                               Snowbrite clay Extender H.B. Fuller Co. 20.20 19.80 12.92                     RHOPLEX MULTILOBE-200 Acrylic Binder Rohm & Haas 16.70 16.37 10.68                                                       Water   32.00 31.37 20.47                                                     Wet Pulp   10.10 9.90 6.46       Grind ingredients 20 min. then add:                                                                          102.00                                                                             100.00                                                                            65.26                                 __________________________________________________________________________                                   wt-%     mixture/cement                                                       Partial                                                                            Total                                                                             wt-%                                  __________________________________________________________________________                                                 60.69                            Cement               Portland Cement Co.                                                                     8.80 16.21                                                                             5.63                                    Mixture  14.50 26.70 9.28                                                     Water  31.00 57.09 19.83                                                        54.30  34.74 100.00                                                       __________________________________________________________________________

                                      TABLE 8                                     __________________________________________________________________________    FRESCO COATING COMPOSITION                                                    __________________________________________________________________________                                   AMOUNT                                                                             Wt-%                                        INGREDIENT FUNCTION MANUFACTURE gram partial Total                          __________________________________________________________________________                                                0.72                              Natrosol 250 MHR                                                                            Thickener                                                                            Aqualon Co.                                                                             12.00                                                                              13.93                                                                             8.64                                    Propylene glycol Solvent Aldrich Chem. Co. 3.20 3.71 8.06                     Methyl carbitol Solvent Aldrich Chem. Co. 3.00 3.48 7.26                      KELZAN, guar gum Dispersant KELCO CO. 0.20 0.23 0.14                          SILWET L-77 Surfactant Union Carbide Co. 0.15 0.17 0.11                       Silica Extender  4.10 4.76 2.95                                               Snowbrite clay Extender H.B. Fuller Co. 20.40 23.58 14.65                     Methyl carbitol Solvent Aldrich Chem. Co. 8.3 9.63 13.17                      Water   11.7 13.58 13.46                                                      Wet pulp Filler  7.2 8.36 5.18                                                RHOPLEX MULTILOBE-200 Acrylic Binder Rohm & Haas 15.70 18.22 11.30                                                       ANTIFOAM 1410 Defoamer Dow                                                   Chemical Co. 0.20 0.23 0.14       Grind ingredients 20 min. then add:                                                                          86.15                                                                              100.00                                                                            85.08                                 __________________________________________________________________________                                   wt-%     mixture/cement                                                       Partial                                                                            Total                                                                             wt-%                                  __________________________________________________________________________                                                60.69                             Cement               Portland Cement Co.                                                                     8.80 16.67                                       Batch #1 Batch #1 15.00 28.41                                                 Methyl carbitol Aldrich Chem. Co. 7.00 13.26                                  Propylene glycol Aldrich Chem. Co. 8.00 15.15                                 Water  14.00 26.52                                                                 58.67                                                                      52.80 100.00                                                              __________________________________________________________________________

                                      TABLE 9                                     __________________________________________________________________________    FRESCO COATING COMPOSITION                                                    __________________________________________________________________________                                   AMOUNT                                                                             Wt-%                                        INGREDIENT FUNCTION MANUFACTURE gram partial Total                          __________________________________________________________________________      TEXANOL Coalescent Eastman Chem. 2.20 2.49 1.56 0.72                            Products                                                                    Natrosol 250 MHR Thickener Aqualon Co. 12.00 13.58 8.50                       Propylene glycol Solvent Aldrich Chem. Co. 3.20 3.62 7.88 0.71                Methyl carbitol Solvent Aldrich Chem. Co. 3.00 3.40 12.96                     KELZAR, guar gum Dispersant KELCO CO. 0.20 0.23 0.14                          SILWET L-77 Surfactant Union Carbide Co. 0.15 0.17 0.11                       Silica Extender  4.10 4.64 2.97                                               Snowbrite clay Extender H.B. Fuller Co. 20.40 23.09 14.45                     Methyl carbitol Solvent Aldrich Chem. Co. 8.3 9.39 0.00                       Water   11.7 13.24 8.29                                                       Wet pulp Filler  7.2 8.15 5.30                                                RHOPLEX HG-74 Acrylic Binder Rohm & Haas 15.70 17.77 11.12                    ANTIFOAM 1410 Defoamer Dow Chemical Co. 0.20 0.23 0.14                      Grind ingredients 20 min. then add:                                                                          88.35                                                                              100.00                                                                            73.16                                 __________________________________________________________________________                                   wt-%     mixture/cement                                                       Partial                                                                            Total                                                                             wt-%                                  __________________________________________________________________________                                                60.69                             Cement               Portland Cement Co.                                                                     8.80 16.67                                       Batch #1 Batch #1 15.00 28.41                                                 Methyi carbitol Aldrich Chem. Co. 7.00 13.26                                  Propylene glycol Aldrich Chem. Co. 8.00 15.15                                 Water  14.00 26.52                                                                 58.67                                                                      52.80 100.00                                                              __________________________________________________________________________

The coating compositions of Tables 1 through 10 above were field testedby applying the subject coating to a 1 foot by 1 foot 1/8th inch thickpressed-wood sample plate. In each instance of field testing, thefollowing procedure was used. First, a primer base coat according to theprimer coating composition of Table 4 was applied to a sample plate andallowed to set and dry for 24 hours. Then a finish Fresco coatingcomposition (i.e. the compositions as set forth in Tables 1 through 3,Table 5 Partial A and Partial B, and Tables 6 through 10 above) wasadmixed with colorant in the ratio of 1 ounce of colorant per pound ofcoating composition and thoroughly mixed for twenty minutes. Next, thefinish Fresco coating composition was admixed with Portland Cement inthe amount of 7 pounds of cement per 10 pounds of coating composition.Then, the finish Fresco coating composition was applied to a sampleplate containing the dried primer base coat with circular and irregulartroweling to obtain a preliminary Fresco-like or marble like, finish.Upon drying of the cement based plaster composition, the applicationprocedure was repeated again with circular and irregular troweling tothis time obtain a final Fresco-like finish. Once the second trowelingtightened into a final finished product, the final Fresco plasterproduced by the finish Fresco coating compositions on the sample plateswas visually inspected for consistency and manually scratch-tested forhardness.

The finish Fresco coating compositions of Tables 1, 2, and 3 provedclearly superior to the finish Fresco coating compositions of Tables 5through 10 as each of the two acrylic polymer cross-linking binderformulations demonstrated upon visual inspection a high consistencywithout observed crazing or shrinkage marks and upon a manualscratch-testing a firm hardness resistant to scratching under normal useconditions.

The Fresco coating composition of Table 5 was prepared in two portions,mainly Partial A and Partial B as listed above. The finish Frescocoating composition of Table 5 Partial A and Partial B as well as thefinish Fresco coating compositions of Tables 6 through 9 each used asingle acrylic binder. Each of these finish Fresco coating compositionsyielded a final Fresco plaster having a Fresco-like coating appearanceon the primer base coated sample plates during the field testingthereof, however each of the final Fresco plasters of these singlebinder finish coating compositions (1) were more difficult to trowelspread on the sample plate than the two acrylic polymer cross-linkingbinder compositions, (2) had present crazing and shrinkage marks inscattered areas of the final Fresco plaster which were observable upon aclose visual inspection, and (3) were easily scratched upon relativelylight contact during the manual scratch-testing. Thus, although thesingle acrylic binder formulations of the Fresco coating compositions ofTables 5 through 10 were suitable to produce a final Fresco plasterhaving a Fresco-like coating appearance, the final Fresco plaster of thetwo acrylic polymer cross-linking binder coating compositions of Tables1 through 4 were superior having a high consistency without observedcrazing or shrinkage marks and a firm hardness resistant to scratchingunder normal use conditions.

                                      TABLE 10                                    __________________________________________________________________________    PRIMER BASE COAT FOR FRESCO COATING COMPOSITION                                                     AMOUNT FOR                                                                            PREFERRED                                         INGREDIENTS FUNCTION WT-% Range 1 Pail %                                    __________________________________________________________________________    Aerosil 200                                                                           Suspender                                                                            0.25-1%                                                                               5.7 oz 0.7%                                               Thickener                                                                    Water  20-50% 21 lbs 42%                                                      Canguard Anti-bacterial 0.05-.25%   1 oz. 0.1%                                 Agents                                                                       Amical Shelf Extender 0.05-.25%   1 oz. 0.1%                                  Texanol Solvent/ 0.2-0.3%  2 oz. 0.24%                                         Coalescent                                                                   Defoamer Defoamer 0.2-0.3%  2 oz. 0.28%                                       Pulp Filler 0.2-0.3%  2.5 oz. 0.28%                                           Water  0.5-2%    8 oz. 1%                                                     Bermocol Thickener 0.25-1%    5.75 oz. .7%                                    Flour Extender 20-40% 17.25 lbs 34.6%                                         AP-200 Pure Latex 2-8%  2 lbs                                                 AP-500 Cross-Linked  8-16%  6 lbs 12%                                          Latex                                                                        Defoamer Defoamer 0.2-0.3%  2.25 oz 0.28%                                         100.00%                                                                 __________________________________________________________________________

The foregoing composition was found to provide an excellent frescofinish when mixed with cement. Also, it was found that the ingredientscould be varied within the ranges given without materially affecting theresulting fresco finish.

From the foregoing description, it will be apparent that the plasterwall surface having a fresco finish, the ingredients from which it ismade and the manner and method by which it is created have a number ofadvantages, some of which have been described above and others of whichare inherent in the invention.

Furthermore, modifications can be made to the composition of the plasterwall, ceiling, or other surface and the mixture of materials andingredients used to make the plaster wall, ceiling, or other surfacewithout departing from the teachings of the present invention.Accordingly, the scope of the invention is only be limited asnecessitated by the accompanying claims.

I claim:
 1. A fresco coating composition which, when admixed with acement-based plaster, produces a material for troweling to obtain afresco finish, said composition being made by combining:a) 10 to 24% byweight of at least one binder selected from the group consistingessentially of an acrylic polymer binder, an acrylic polymer binder andan acrylic polymer cross-linking binder; b) 20 to 50% by weight ofwater; c) 2 to 8% by weight of a filler selected from the groupconsisting essentially of cellulose, paper pulp, or mixtures thereof; d)20 to 40% by weight of at least one water-insoluble particulate extenderincluding silica sand; e) 0.5 to 2% by weight of a thickening agent; f)optionally at least one of a solvent, a coalescence promoter, a foaminhibitor, a biocide and mixtures thereof.
 2. The fresco coatingcomposition of claim 1 including 0.2 to 3% by weight of solvents.
 3. Thefresco coating composition of claim 1 including 0.2 to 0.3% by weight ofcoalescence promoters.
 4. The fresco coating composition of claim 1including 0.2 to 0.6% by weight of foam inhibitors.
 5. The frescocoating composition of claim 1 including 0.05 to 0.5% by weight ofbiocides.
 6. The fresco coating composition of claim 1 including 0.05 to0.25% by weight of anti bacterial agent.
 7. The fresco coatingcomposition of claim 1 including 0.05 to 0.25% by weight ofpreservative/shelf extender.
 8. The fresco coating composition of claim1 including 2 to 6% by weight of acrylic polymer binder.
 9. The frescocoating composition of claim 1 including 8 to 16% by weight of acrylicpolymer cross-linking binder.
 10. The fresco coating composition ofclaim 1 wherein said thickening agent includes 0.25 to 7% by weightsuspender.
 11. The fresco coating composition of claim 1 including:4% byweight of acrylic polymer binder; 12% by weight of acrylic cross-linkingbinder; 43% by weight of water; 4% by weight of a filler selected fromthe group consisting essentially of cellulose, paper pulp, or mixturesthereof; 34.6% by weight of at least one water-insoluble particulateextender including silica sand; 1.4% by weight of a thickening agent;0.2% by weight of biocides; 0.24% by weight of solvent/coalescencepromoter; and, 0.56% by weight of a foam inhibitor.
 12. The frescocoating composition of claim 1 including 2 to 8% by weight of acolorant.